Figure 4. QD loading.

(a) TEM image of a QD/TiO₂ heterojunction showing the intimate contact between them when tBA is used as a ligand. Scale bar, 5 nm. (b) SEM cross-sectional image of our champion device. The substrate used was fluorinated tin oxide (FTO)-coated glass. Scale bar, 10 μm. (c) EDX spectroscopy line scan of the cross-section showing the elemental composition of the sensitized film. Atomic percentages are of the total composition excluding oxygen (not shown) and tin (shown in orange, but arbitrarily scaled), and the titanium atomic percent is scaled down by a factor of 10 for ease of comparison.